The present invention relates in general to tractor drawn lift bed trailers for transporting high tonage loads over the highway, utilizing pallet frame units adapted to be picked up or dropped off quickly without the need for additional equipment or personnel. The combination of lift bed trailer and detachable pallet frame units maximizes the availability of the trailer for load carrying and greatly increases the efficiency of the equipment. This invention represents an improvement over the lift bed trailers disclosed in prior U.S. Pat. Nos. 4,061,353 and 4,060,145 issued on the application of Kingman et al., U.S. Pat. No. 4,050,709 issued on the application of Eugene A. LeBoeuf, and co-pending U.S. application Ser. No. 315,437 of Leslie A. Weaver, now U.S. Pat. No. 4,474,359.